The utility model provides a gas turbine's exhaust gas circulation utilizes system and operational method, owing to be equipped with the feedback pipeline between the induction port at the compressor and the gas vent of turbine, be equipped with flow control valve on the feedback pipeline, can recycle the hot gas recovery of turbine gas vent exhaust from the inspiratory air mixing of environment to the compressor in and with the compressor through the feedback pipeline so together, thereby the gas temperature of compressor has been improved, the required fuel in combustion chamber has been reduced, thereby gas turbine's under the partial load overall efficiency has been improved, and controlling means can control flow control valve's size according to a temperature sensor, a pressure sensor, the 2nd temperature sensor and the 2nd pressure sensor's detected signal to can adjust the intake air temperature of gas turbine compressor according to gas turbine's operating condition and ambient air's state intelligently, thereby improve overall efficiency.